Recovery system for test missiles



March 1963 H. l. SHALLER RECOVERY SYSTEM FOR TEST MISSILES 2 Sheets-Sheet 1 Filed Sept. 28, 1960 INVENTOR HERMAN SHALLEI? ATTORNEYS AGENT March 19, 1963 H. I; SHALLER 3,031,626

RECOVERY SYSTEM FOR TEST MISSILES Filed Sept. 28, 1960 2 Sheets-Sheet 2 IOO Disfance of cable travel and velocity INVENTOR HERMAN SHALLER ATTORNEYS Y mam AGE/VT 3,081,626 RECOVERY SYSTEM FOR TEST MISSILES Herman I. Shaller, Silver Spring, Md., assignor to the United States of America as represented by the Secretary f the Navy Filed Sept. 28, 1960, Ser. No. 59,121 4 Claims. (Cl. 73-167) (Granted under Title 35, US. Code (1952), see. 266) United The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payis first necessary to catapult the missile into the air be-- fore igniting the rocket engines because the ship can not withstand the effects of the heat generated by the rocket motors. Another application wherein it is necessary to catapult the missile into the air before igniting the rocket engines is when a missile is launched from a mobile platform such as a truck or a railroad car. In these instances, a tube is utilized to provide a shockproof store for the missile during the time prior to launching, as well as, to launch the missile. The missile is normally ejected from the vertical tube by gas pressure which is generated in any one of several conventional manners.

Difiiculties encountered in the design and development of these launching tubes have been many. Consequently, it has been necessary to build or construct intricate test complexes whichwill permit the testing of these launching tubes under simulated operational conditions. The missiles ejected from theselaunching tubes usually weigh between 3 0,000 and 100,000 pounds with the number of missiles which are ejected from such a test complex running into the thousands. In view. of the fact that each test missile is heavily instrumented in order to determine the performance characteristics of the launching tube, it has been necessary to build devicesfor preserving these test missiles for reuse. Obviously, if a test missile were allowed to fall back to the earth it would be damaged severely and not be reusable.

In utilizing the present invention, the test missile has a cable connected thereto which cable is then drawn through a pulley mounted between two towers. The towers are of such height that they will not permit the test missile to be fired thereabove. Means are provided for absorbing the slack inthe' cable as themissile is ejected. Once the missilereaches its highest apogee the slack absorbing means will not permit the cable absorbed to be released thereby suspending the missile in mid-air. The missile is then lowered slowly back to the ground by a controlled release of the slack absorbing means.

Accordingly, one object of the present invention is to provide a slack absorbing means for a ballistic missile recovery system.

Yet another object of the instant invention is to provide a ballistic missile recovery system which system provides a minimum number of system failures.

Another object of this invention resides in the provision of a slack absorbing means which is simple in construction and oifers a maximum of dependability.

Still another object of this invention is to provide a slack absorbing means for a missile test complex which Patented Mar. 19, 1963 ice is simple in construction and relatively inexpensive to manufacture and operate.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view of the missile testing complex shown in readiness for launching a test ballistic missile;

FIG. 2 is a front view of the complex illustrated in FIG. 1;

FIG. 3 is a partial section along the line 33 of FIG. 2;

FIG. 4'is a detailed view of the slack absorbing means; and

FIG. 5 illustrates comparative graphs of the inventive system in operation.

Referring to FIGS. 1 and 2 of the drawings, the reference numeral 11 indicates a ballistic test missile which is'to be ejected from a launcher tube 12 in a generally vertical direction under the force of high fluid pressure which is supplied to the launcher tube 14 at a point below the missile 11 by the conduit 14. The launcher complex 13 is disposed below the surface of the ground 10, although it can be placed on or above the surface, as desired. The launcher 12 is mounted in a manner, not shown, to permit movement which simulates actual sea-going ship conditions thereby testing the launcher under actual conditions which a submarine or surface ship would encounter.

Upright towers and 16 may be constructed of any conventional material and supported by guy lines, not shown. It is within the scope of the present invention to construct this test complex with one tower having a cantilever boom projecting therefrom. The towers rise above the calculated ejection height of the test missile and are spanned at their uppermost points by a cable 17 having an end secured to each tower, thereby providing an overhead support.

Secured to the cable 17 at a point mid-way between the towers is a swivelable pulley 18 over which travels a flexible cable, chain, rope, or the like 19. One end of this cable is secured to the test missile 11 by conventional means. The other end of the cable '19 is threaded through a cable take-up and arresting means illustrated in the form of a block and tackle arrangement or pulley system and a ratchet device, as shown in FIG. 4. The block and tackle or pulley system arrangement consists of six pulleys 21, 22., 23, 24, 25, and 26. Pulleys 21, 22, and 23 are rotatably supported by interconnecting link 27. Link 27 is rigidly fastened to the uppermost part of tower 15 by conventional fastening means 28. The pulleys 24', 25, and 26 are rotatably interconnected by, link 29 in the same manner as link 27 interconnects pulleys 21, 22, and 23 except that link 29 is free to move vertically with respect to the tower '15. Secured to the link 29 is a counterweight W which is operable to move vertically with the link 29 and its respective pulleys. As will be explained in more detail hereinafter, the mass of the Weight W is equal to slightly more than the mass of cable 19 plus the friction of the pulley arrangement. A tubular shaped guide 3% is provided within the tower 15 in a manner to permit the weight W to move vertically without restriction. That is, guide 30 permits the weight W to move vertically free from contact with the struts of tower 15. The guide 30 is of suflicient diameter to permit the link 29 and its pulleys to move therein as shown by the dotted lines in FIG. 3.

A toothed ratchet wheel 40 is rigidly secured to pulley 21 and is engaged by lever 4-1 which rotates about fulcrum 42 thereby permitting engagement and disengagement of the projection 43 with the teeth of the wheel 40. A rigid rod 44 is manually operated at 45 to effect engagement and disengagement of the projection 43 with the toothed wheel 40. When the projection 43 is engaged the ratchet effect of wheel 40 will permit the pulley 21 to move freely in a counter clockwise direction as viewed in FIG. 4. However, when the projection 43 is disengaged the pulley may move freely in either direction. Of course, many other expedients may be utilized to permit a releasable unidirectional rotation of the pulley 21 without departing from the scope of this invention.

In operation, the missile 13 with the cable 19 attached thereto is loaded into the launcher tube :12. When the fluid pressure is injected into the space below the missile, the missile is forced vertically into the air. As the missile is ejected from the launcher tube, the cable becomes slack. However, since the weight W has a mass greater than the mass of cable 19 plus the mass equivalent of the friction of the pulley system, the Weight W immediately begins to descend thereby absorbing the cable slack. Due to the particular pulley arrangement, the weight descends only a fraction of the distance that the missile ascends. As the missile 11 reaches its apogee and begins to fall, the cable direction through the pulley system is reversed thereby causing pulley 21 to reverse its direction. Since the projection 43 is normally in the engaged position the pulley 21 is prohibited from rotating in a clockwise direction. Therefore, cable 19 will not reverse its direction and the missile will be supported in mid-air at or very close to its apogee by the instant invention. To lower the missile back to the ground, it is merely necessary to alternately disengage and engage the brake mechanism through operation of manual means 45 thereby gradually lowering the missile to the ground. Contact between pulley 21 and cable '19 is slip-proof. Should the weight of the missile become so great as to cause slippage in the device shown, of course, another conventional brake or lock mechanism could be substituted without departing from the scope of this invention.

FIG. of the drawing shows the general performance characteristics of this improved test complex. The curve 1 illustrates the vertical distance of cable travel at any point on the cable on the missile side of the pulley 21. The portion of curve 11 indicated between reference characters a and 11 indicates the distance in which missile is traveling through the launcher tube. Graph 2 illustrates the vertical distance that the cable travels on the counterweight side of pulley 21. The divergence between curves 1 and 2 during the initial movement of the missile illustrates the portion in which there is cable slack. It is noted that this slack period is during the high acceleration period when the missile is traveling in the launcher tube. Obviously, this travel is of relatively short distance compared with the external travel of the missile and consequently the slack is minor and unobjectionable. Graph 3 ilustrates the missile velocity through the ejection and external flight. FIG. 4 indicates the comparative velocity of the weight W during the slack absorbing operation.

The particular block and tackle 0r pulley system arrangemen-t can be modified within certain limits to permit the absorbing of cable slack with more or less movement of the weight W. This may be done by increasing or decreasing the number of pulleys.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a test rig for catching a missile in mid-air having two spaced towers each having an uppermost portion, a first cable supported between the uppermost portions of said towers and spanning the space therebetween, a pulley mounted intermediate said towers on said cable, a second cable connectable to the missile and looped over said pulley, means to launch the missile into the air, an

improved cable slack absorbing means comprising, a block and tackle means supported at the top of one of said towers, said second cable being attached thereto, counterweight means attached to said block and tackle means in a manner to cause the block and tackle to absorb the cable slack when the missile is ejected into the air, and releasable means to permit one-way cable movement therethrough to cause the missile to be supported by said cable in mid-air at the apogee of its test trajectory.

2. The device set forth in claim 1 wherein said block and tackle means comprises two sets of pulleys, one of i said sets of pulleys being rigidly secured to said tower, and said other set of pulleys having said counterweight rigidly secured thereto, said second mentioned set ofpulleys being movable vertically.

3. The improved cable slack absorbing means as set forth in claim 2 wherein said counterweight has a mass slightly greater than the mass of the said cable plus the mass equivalent of the friction of said pulley and said block and tackle means.

4. In a test complex for testing ballistic missile launchers by ejecting test missiles into the air, recovery means for catching said missile at its apogee comprising two spaced tower means having upper portions, cable means having an end secured to each of said upper portions whereby said cable means spans the space between said towers, a freely rotatable pulley supported by said cable means intermediate the ends of said cable means, a cable take-up means, a cable attached at one end to said missile and threaded over said pulley and connected at its other end to said cable take-up means, and releasable arresting means operably connected to said cable take-up means in a manner to permit unidirectional movement of said cable whereby when the missile is ejected into the air the cable take-up means cause absorption of cable slack and when the missile reaches its apogee the releasable arresting means will prevent the release of the cable thereby suspending the missile in mid-air.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A TEST RIG FOR CATCHING A MISSILE IN MID-AIR HAVING TWO SPACED TOWERS EACH HAVING AN UPPERMOST PORTION, A FIRST CABLE SUPPORTED BETWEEN THE UPPERMOST PORTIONS OF SAID TOWERS AND SPANNING THE SPACE THEREBETWEEN, A PULLEY MOUNTED INTERMEDIATE SAID TOWERS ON SAID CABLE, A SECOND CABLE CONNECTABLE TO THE MISSILE AND LOOPED OVER SAID PULLEY, MEANS TO LAUNCH THE MISSILE INTO THE AIR, AN IMPROVED CABLE SLACK ABSORBING MEANS COMPRISING, A BLOCK AND TACKLE MEANS SUPPORTED AT THE TOP OF ONE OF SAID TOWERS, SAID SECOND CABLE BEING ATTACHED THERETO, COUNTERWEIGHT MEANS ATTACHED TO SAID BLOCK AND TACKLE MEANS IN A MANNER TO CAUSE THE BLOCK AND TACKLE TO ABSORB THE CABLE SLACK WHEN THE MISSILE IS EJECTED INTO THE AIR, AND RELEASABLE MEANS TO PERMIT ONE-WAY CABLE MOVEMENT THERE- 